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The Cretaceous–Paleogene (K–Pg) extinction event, [a] also known as the K–T extinction, [b] was the mass extinction of three-quarters of the plant and animal species on Earth [2] [3] approximately 66 million years ago. The event caused the extinction of all non-avian dinosaurs.
Because the estimated date of the object's impact and the Cretaceous–Paleogene boundary (K–Pg boundary) coincide, there is now a scientific consensus that this impact was the Cretaceous–Paleogene extinction event which caused the death of most of the planet's non-avian dinosaurs and many other species.
By the Cretaceous period, abelisauroids had apparently become extinct in Asia and North America, possibly due to competition from tyrannosauroids. However, advanced abelisauroids of the family Abelisauridae persisted in the southern continents until the Cretaceous–Paleogene extinction event 66 million years ago. [13]
The Cretaceous Terrestrial Revolution (abbreviated KTR), also known as the Angiosperm Terrestrial Revolution (ATR) by authors who consider it to have lasted into the Palaeogene, [1] describes the intense floral diversification of flowering plants (angiosperms) and the coevolution of pollinating insects, as well as the subsequent faunal radiation of frugivorous, nectarivorous and insectivorous ...
The Cretaceous is the Phanerozoic's longest period and the last period of the Mesozoic. It spans from 145 million to 66 million years ago, and is divided into two epochs: Early Cretaceous , and Late Cretaceous .
The Cretaceous (along with the Mesozoic) ended with the Cretaceous–Paleogene extinction event, a large mass extinction in which many groups, including non-avian dinosaurs, pterosaurs, and large marine reptiles, died out, widely thought to have been caused by the impact of a large asteroid that formed the Chicxulub crater in the Gulf of Mexico.
According to the Tertiary radiation hypothesis, [a] they evolved after the Cretaceous–Paleogene extinction event from multiple flying ancestors on multiple continents around the world. This hypothesis is supported by molecular phylogeny studies and matches the fossil record, but it is weakened by morphological phylogenetic studies.
Its age is usually estimated at 66 million years, [2] with radiometric dating yielding a more precise age of 66.043 ± 0.043 Ma. [3] The K–Pg boundary is associated with the Cretaceous–Paleogene extinction event, a mass extinction which destroyed a majority of the world's Mesozoic species, including all dinosaurs except for some birds. [4]